Tiacumicin Production

ABSTRACT

Methods, processes and materials for the production and recovery of Tiacumicins produced by culturing a microorganism belonging to the species  Dactylosporangium aurantiacum  subspecies  hamdenensis  having the ability to produce and accumulate one or more Tiacumicin in a nutrient medium comprising a carbon source, a nitrogen source, trace elements such as inorganic salts, and an adsorbent, wherein said nitrogen source comprises fish powder, and wherein said Tiacumicin is produced in a yield greater than about 50 mg/L broth.

BACKGROUND OF THE INVENTION

Tiacumicins are a family of structurally related compounds that containthe 18-membered macrolide ring shown below.

At present, several distinct Tiacumicins have been identified and six ofthese (Tiacumicin A-F) are defined by their particular pattern ofsubstituents R¹, R², and R³ (U.S. Pat. No. 4,918,174; J. Antibiotics,1987, 575-588).

The Lipiarmycins are a family of natural products closely related to theTiacumicins. Two members of the Lipiarmycin family (A3 and B3) areidentical to Tiacumicins B and C respectively (J. Antibiotics, 1988,308-315; J. Chem. Soc. Perkin Trans I, 1987, 1353-1359).

The Tiacumicins and the Lipiarmycins have been characterized by numerousphysical methods. The reported chemical structures of these compoundsare based on spectroscopy (UV-vis, IR and ¹H and ¹³C NMR), massspectrometry and elemental analysis (See for example: J. Antibiotics,1987, 575-588; J. Antibiotics, 1983, 1312-1322).

Tiacumicins are produced by bacteria, including Dactylosporangiumaurantiacum subspecies hamdenensis, which may be obtained from the ARSPatent Collection of the Northern Regional Research Center, UnitedStates Department of Agriculture, 1815 North University Street, Peoria,Ill. 61604, accession number NRRL 18085. The characteristics of strainAB 718C-41 are given in J. Antibiotics, 1987, 567-574 and U.S. Pat. No.4,918,174.

Lipiarmycins are produced by bacteria including Actinoplanes deccanensis(U.S. Pat. No. 3,978,211). Taxonomical studies of type strain A/10655,which has been deposited in the ATCC under the number 21983, arediscussed in J. Antibiotics, 1975, 247-25.

Tiacumicins, specifically Tiacumicin B, show activity against a varietyof bacterial pathogens and in particular against Clostridium difficile,a Gram-positive bacterium (Antimicrob. Agents Chemother. 1991,1108-1111). Clostridium difficile is an anaerobic spore-formingbacterium that causes an infection of the bowel. Diarrhea is the mostcommon symptom but abdominal pain and fever may also occur. Clostridiumdifficile is a major causative agent of colitis (inflammation of thecolon) and diarrhea that may occur following antibiotic intake. Thisbacterium is primarily acquired in hospitals and chronic carefacilities. Because Tiacumicin B shows promising activity against C.difficile, it is expected to be useful in the treatment of bacterialinfections, especially those of the gastrointestinal tract, in mammals.Examples of such treatments include but are not limited to treatment ofcolitis and treatment of irritable bowel syndrome. Tiacumicins may alsofind use for the treatment of gastrointestinal cancers.

Fermentation processes are used to obtain antibiotics, includingTiacumicins. Antibiotics may be produced by culturing a microorganism ina medium containing readily assimilated sources of carbon, nitrogen, andinorganic salts under submerged aerobic fermentation conditions, until asubstantial amount of antibiotic activity is produced as deduced fromin-process analyses. Because of rising worldwide demand for antibiotics,there is an ongoing need for improved methods to produce antibiotics.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an HPLC chromatogram of crude fermentation productsproduced according to Example 1; Tiacumicin B has a retention time ofapproximately 12.6 min.

FIG. 2 shows an HPLC chromatogram of fermentation products producedaccording to Example 2; Tiacumicin B has a retention time ofapproximately 11.8 min.

FIG. 3 shows an HPLC chromatogram of purified (by HPLC) Tiacumicin Bproduced by fermentation according to Example 2; Tiacumicin B has aretention time of approximately 12.0 min.

FIG. 4 shows an HPLC chromatogram of Tiacumicin B produced byfermentation and purified by reverse phase medium pressure liquidchromatography followed by trituration according to Example 3;Tiacumicin B has a retention time of approximately 10.1 min.

SUMMARY OF THE INVENTION

The present invention presents methods, processes and materials for theproduction of Tiacumicins. The present invention also presentsTiacumicins produced using the fermentation methods, processes, andmaterials described herein.

One embodiment of the present invention comprises a process forproducing Tiacumicins which comprises culturing a microorganismbelonging to the species Dactylosporangium aurantiacum subspecieshamdenensis having the ability to produce Tiacumicins in a nutrientmedium and accumulating at least one Tiacumicin in the nutrient medium,wherein the yield of at least one Tiacumicin is greater than about 50mg/L broth.

In one embodiment of the invention, improved media and conditions forthe fermentative production of Tiacumicin B are described. Thus, oneembodiment of the present invention is a nutrient medium for productionof Tiacumicins comprising a carbon source, a nitrogen source, traceelements such as inorganic salts, and an adsorbent, wherein saidnitrogen source comprises fish powder, and wherein said nutrient mediumis used to produce one or more Tiacumicin in a yield greater than about50 mg/L broth.

In another embodiment of the invention, an improved recovery method,resin adsorption of Tiacumicin B is described.

Another embodiment of the invention involves using bacterial strainsrelated to Dactylosporangium aurantiacum subspecies hamdenensis, asorganisms for producing Tiacumicins. Thus, the present inventionincludes a Tiacumicin produced by culturing a microorganism belonging tothe species Dactylosporangium aurantiacum subspecies hamdenensis havingthe ability to produce and accumulate one or more Tiacumicin in anutrient medium comprising a carbon source, a nitrogen source, traceelements such as inorganic salts, and an adsorbent, wherein saidnitrogen source comprises fish powder, and wherein said Tiacumicin isproduced in a yield greater than about 50 mg/L broth.

Another embodiment of the invention involves the use of reverse phasemedium pressure liquid chromatography and/or liquid/liquid partitionand/or trituration for the purification of Tiacumicins from the crudefermentation product.

These improvements, alone or together, allow the fermentative productionand recovery of Tiacumicin B in much improved yield (>50 mg/L broth).

DETAILED DESCRIPTION OF THE INVENTION

All patents, publications and patent applications referred to herein arehereby incorporated by reference in their entireties. Unless otherwisedefined, all technical and scientific terms used herein have the samemeaning as commonly understood by one of ordinary skill in the art towhich this invention belongs. Exemplary methods and materials aredescribed below. However, methods and materials similar or equivalent tothose described herein can be also used to obtain variations of thepresent invention. The materials, methods, and examples are illustrativeonly and not intended to be limiting.

The compositions containing the Tiacumicins of the invention can beadministered for prophylactic and/or therapeutic treatments. Intherapeutic applications, the compositions are administered to a patientalready suffering from an infection, as described above, in an amountsufficient to cure or at least partially arrest the symptoms of theinfection. An amount adequate to accomplish this is defined as“therapeutically effective amount or dose.” Amounts effective for thisuse will depend on the severity and course of the infection, previoustherapy, the patient's health status and response to the drugs, and thejudgment of the treating physician. In prophylactic applications,compositions containing the Tiacumicins of the invention areadministered to a patient susceptible to or otherwise at risk of aparticular infection. Such an amount is defined to be a“prophylactically effective amount or dose.” In this use, the preciseamounts again depend on the patient's state of health, weight, and thelike.

Once improvement of the patient's conditions has occurred, a maintenancedose is administered if necessary. Subsequently, the dosage or thefrequency of administration, or both, can be reduced, as a function ofthe symptoms, to a level at which the improved condition is retained.When the symptoms have been alleviated to the desired level, treatmentcan cease. Patients can, however, require intermittent treatment on along-term basis upon any recurrence of the disease symptoms.

In general, a suitable effective dose of the Tiacumicins of the presentinvention will be in the range of 0.1 to 1000 milligrams (mg) perrecipient per day, preferably in the range of 1 to 500 mg per day. Thedesired dosage is preferably presented in one, two, three, four or moresubdoses administered at appropriate intervals throughout the day. Thesesubdoses can be administered as unit dosage forms, for example,containing 5 to 1000 mg, preferably 10 to 200 mg of active ingredientper unit dosage form. Preferably, the compounds of the invention will beadministered in amounts of between about 1.0 mg/kg to 250 mg/kg ofpatient body weight, between about one to four times per day.

A “pharmacological composition” refers to a mixture of one or more ofthe Tiacumicins described herein, or physiologically acceptable saltsthereof, with other chemical components, such as physiologicallyacceptable carriers and/or excipients. The purpose of a pharmacologicalcomposition is to facilitate administration of a compound to anorganism.

“Pharmaceutically acceptable salts” of the compounds of the inventioninclude those derived from pharmaceutically acceptable inorganic andorganic acids and bases. Examples of suitable acids includehydrochloric, hydrobromic, sulfuric, nitric, perchloric, fumaric,maleic, phosphoric, glycolic, gluconic, lactic, salicylic, succinic,toluene-p-sulfonic, tartaric, acetic, citric, methanesulfonic, formic,benzoic, malonic, naphthalene-2-sulfonic, benzenesulfonic, 1,2ethanesulfonic acid (edisylate), galactosyl-D-gluconic acid, and thelike. Other acids, such as oxalic acid, while not themselvespharmaceutically acceptable, may be employed in the preparation of saltsuseful as intermediates in obtaining the compounds of this invention andtheir pharmaceutically acceptable acid addition salts. Salts derivedfrom appropriate bases include alkali metal (e.g., sodium), alkalineearth metal (e.g., magnesium), ammonium and N(C₁-C₄ alkyl)₄ ⁺ salts, andthe like. Illustrative examples of some of these include sodiumhydroxide, potassium hydroxide, choline hydroxide, sodium carbonate, andthe like.

A “physiologically acceptable carrier” refers to a carrier or diluentthat does not cause significant irritation to an organism and does notabrogate the biological activity and properties of the administeredcompound.

An “excipient” refers to an inert substance added to a pharmacologicalcomposition to further facilitate administration of a compound. Examplesof excipients include but are not limited to, calcium carbonate, calciumphosphate, various sugars and types of starch, cellulose derivatives,gelatin, vegetable oils and polyethylene glycols.

The term “nutrient medium” as used herein describes a mixture ofsynthetic or naturally occurring ingredients. In general, a nutrientmedium comprises a carbon source, a nitrogen source, trace elements suchas inorganic salts, and optionally vitamins or other growth factors, andan adsorbent.

The term “broth” as used herein refers to the fluid culture medium asobtained during or after fermentation. Broth comprises a mixture ofwater, the desired antibiotic(s), unused nutrients, living or deadorganisms, metabolic products, and the adsorbent with or withoutadsorbed product.

The term “Tiacumicin” as used herein refers to a family of compounds allof which comprise the 18-membered macrolide ring shown below:

The term “Tiacumicin B” refers to molecule having the structure shownbelow:

The term “yield” as used herein refers to an amount of crude Tiacumicinre-constituted in methanol to the same volume as the originalfermentation broth. Yield is determined using standard HPLC techniques.Yield is reported in units of mg/L.

One embodiment of the invention comprises a process suitable forproducing antibiotic agents, for example Tiacumicins, by submergedaerobic fermentation of the microorganism. One embodiment of such anorganism is Dactylosporangium aurantiacum subspecies hamdenensi.According to one embodiment of the invention, Tiacumicins, for exampleTiacumicin B, are recovered in exceptional yield (>100 mg/L broth) fromthe fermentation broth by resin absorption and eluted from the resin andmycelium by washing with solvents of various polarities. Purificationmay be furthered by solvent extraction and/or chromatographic separationsuch as Sephadex, silica gel, High-Performance Liquid Chromatography(HPLC) or reverse phase medium pressure liquid chromatography and/orrecrystallization with one or more solvents and/or trituration with oneor more solvents.

One microorganism employed in this invention was identified as belongingto the family Actinoplanaceae, genus Dactylosporangium (Journal ofAntibiotics, 1987, p. 567-574 and U.S. Pat. No. 4,918,174). It has beendesignated Dactylosporangium aurantiacum subspecies hamdenensis 718C-41.The subculture was obtained from the ARS Patent Collection of theNorthern Regional Research Center, United States Department ofAgriculture, 1815 North University Street, Peoria, Ill. 61604, U.S.A.,where it was assigned accession number NRRL 18085. The characteristicsof strain AB 718C-41 are given in the Journal of Antibiotics, 1987, p.567-574 and U.S. Pat. No. 4,918,174.

Additional microorganisms capable of producing Tiacumicins includemutant species, which show advantageous properties compared with speciesknown in the art. Such bacterial strains can be generated by mutagenesisof a parent strain. Strategies and methods of mutagenesis, proceduresfor screening and isolation of mutated bacterial strains, compositionsof media used in producing the mutant strains of the invention are knownin the art. Microorganisms designated as strains may embody advantagessuch increased production of desired macrolide, more efficient usage ofnutrient media, or decreased requirement of oxygen for aerobic growth.

In the preferred embodiment, cultivation of Dactylosporangiumaurantiacum subspecies hamdenensis AB 718C-41 NRRL 18085 for theproduction of the Tiacumicins is carried out in a medium containingreadily assimilable carbon sources, nitrogen sources, inorganic saltsand other organic ingredients with one or more absorbents under properaeration conditions and mixing in a sterile environment. Compositions ofnutrient media used in producing antibiotics of the invention will bedescribed in detail in the examples.

Carbon sources capable of supporting microorganism growth include butare not limited to glucose, sucrose, galactose, fructose, starch,molasses, malt extracts, dextrins, whey, glycerol, lipids, corn meal andthe like and combinations thereof. According to one embodiment of theinvention, the carbon source is present in the range between 0.2-10% byweight. Amounts of carbon sources according to one embodiment of theinvention are given in Table 2.

Nitrogen sources capable of supporting microorganism growth include butare not limited to beef extract, soybean meal, cottonseed meal, wholeyeast, yeast extract, soybean flour, peptone, casamino acid, fishpowder, corn steep liquor, ammonium salts, casein, amino acids and thelike and combinations thereof. According to one embodiment of thepresent invention, the nutrient medium contains fish powder (999 Primequality fishmeal, TripelNine Fish Protein, a.m.b.a. Fiskerihavnsgade 35,6700 Esbjerg, Demark) as the nitrogen source. According to oneembodiment of the invention, the nitrogen source is present in the rangebetween 0.1-5.0% by weight. Amounts of nitrogen sources according to oneembodiment of the invention are given in Table 2.

Essential trace elements necessary for the growth and development of theorganism may occur as impurities in other constituents of the media inamounts sufficient to meet the growth and biosynthetic requirements ofthe organism. However, it may be beneficial to incorporate in theculture media additional soluble nutrient inorganic salts capable ofassisting microorganism growth. Inorganic salts capable of supportingmicroorganism growth include but are not limited to K₂HPO₄, MgSO₄.7H₂O,KCl, CaCO₃ and the like. Essential trace elements are preferably presentin the range between 0.02-2.0% by weight. Amounts of individualessential elements according to one embodiment of the invention aregiven in Table 2.

Commercially available adsorbent resins were found to enhance the yieldand recovery efficiency of Tiacumicins during the fermentation. Suchadsorbents include but are not limited to Amberlite® XAD16, XAD16HP,XAD2, XAD7HP, XAD1180, XAD1600, and IRC50 (all Rohm & Haas Co., U.S.A.),Duolite® XAD761 (Rohm & Haas Co., U.S.A.) and the like. Adsorbents arepreferably present in the range between 0.5-15% by weight. Amounts ofadsorbents according to one embodiment of the invention are given inTable 2.

As is customary in aerobic submerged culture processes, sterile air isdispersed through the culture medium. The oxygen concentration was keptat higher than 3% (InPro 6000 series O₂ sensors, Mettler Toledo). Underthese conditions the growth of cells is maintained at a level thatprevents the growth conditions becoming anaerobic. In some embodiments,the limiting component is chosen from a carbon source, nitrogen source,or any other component required by the cells (e.g., in the feed medium).

Bacteria are grown under suitable growth conditions. Such suitablegrowth conditions are characterized by limiting the availability of acomponent of the growth medium and/or feed medium in such a way thataerobic conditions for the growth of said bacterium are maintained. Suchconditions can be also characterized e.g. by maintaining a level ofdissolved oxygen at a concentration between about 2% to 30%. Such levelsof dissolved oxygen can vary depending on the specific technicalequipment used for growing bacteria and for measuring the dissolvedoxygen concentration.

Tiacumicin-producing bacteria can be grown in vessels ranging from shakeflasks to large “batch” fermenters, by methods known in the art. Forproducing substantial quantities of Tiacumicins, submerged aerobicfermentation in tanks is utilized. However, small amounts may beobtained by shake-flask culture. For tank fermentation, it is preferableto use a vegetative inoculum. The vegetative inoculum is prepared byinoculating a small volume of culture medium with the spore form,mycelial fragments, or a lyophilized pellet of the organism to obtain afresh, actively growing culture of the organism. The vegetative inoculumis then transferred to a larger tank where, after a suitable incubationtime, the Tiacumicin antibiotic is produced in much improved yield.

It may be necessary to add small amounts of an antifoam agent tolarge-scale fermentation media if foaming becomes a problem.

The production proceeds in a control medium with otheradditives/ingredients to improve the production. A liquid-submerged,stirred-culture process is used for the production of Tiacumicins.Fermentation is carried out at a temperature range of 25° C. to 37° C.The consumption of the carbon source is carefully monitored and anadditional amount of carbon source is added as needed. The pH of thefermentation is preferably maintained between about 6.0 to about 8.0.Tiacumicin B is produced and accumulated between 3 to 15 days afterinoculation of the fermentation. The standard control medium consists ofthe following ingredients in the following quantities:

-   Fish powder 0.1% to 5%-   Glucose 0.2% to 10%-   K₂HPO₄ 0.02% to 0.5%-   MgSO₄.7H₂O 0.02% to 0.5%-   KCl 0.01% to 0.3%-   CaCO₃ 0.1% to 2%    Other additives/ingredients consist of:-   Casamino acid 0.05% to 2%,-   Yeast extract 0.05% to 2%-   XAD-16 resin 0.5% to 15%

Upon completion of fermentation, the solid mass (including the adsorbentresin) is separated from the broth by sieving. Tiacumicins are elutedfrom the resin with organic solvents such as ethyl acetate, methanol,acetonitrile or a mixture of two or more organic solvents. The extractis then concentrated under reduced pressure. This residue is furtherpurified by trituration with low polarity solvents such as hexanes,heptanes, methylcyclohexane, or by partitioning between two phasesolvent systems such as: ethyl acetate/water; ethyl acetate/aqueoussodium chloride solution; methanol/hexane, acetonitrile/hexane or othermixtures of two or more solvents in various ratios and combinations orby Sephadex column chromatography eluting with an appropriate organicsolvent system. If needed, Tiacumicins can be further purified either bycrystallization, and/or chromatographic separation and/orHigh-Performance Liquid Chromatography (HPLC) and/or liquid/liquidpartitioning and/or trituration.

EXAMPLES

As can be appreciated from the disclosure above, the present inventionhas a wide variety of applications. Accordingly, the following examplesare offered by way of illustration, not by way of limitation.

Example 1

Dactylosporangium aurantiacum subsp. hamdenensis AB 718C-41 NRRL 18085(−20° C. stock), was maintained on 1 mL of Medium No. 104 (Table 1).After standard sterilization conditions (30 min., 121° C., 1.05 kg/cm²)the seed flask (250 mL) containing Medium No. 104 (50 mL) was inoculatedwith AB 718C-41 NRRL 18085 on a shaker (set @250 rpm) at 30° C. for 72hr. Five percent vegetative inoculum from the first passage seed flaskwas then transferred aseptically to a fermentation flask containing thesame ingredients as in Table 1.

TABLE 1 Ingredients of Medium No. 104 Fish Casamino Yeast powder GlucoseK₂HPO₄ MgSO₄7H₂O KCl CaCO₃ acid extract XAD-16 10 g/L 20 g/L 0.5 g/L 0.5g/L 0.3 g/L 3 g/L 2.5 g/L 2.5 g/L 20 g/L

Fermentation flasks were incubated on a rotary shaker at 30° C. for 3 to12 days. Samples of the whole culture fermentation broth were filtered.The filter cake was washed with MeOH and solvents were removed underreduced pressure. The residue was re-constituted in methanol to the samevolume of the original fermentation broth. Analysis was performed usinga Waters BREEZE HPLC system coupling with Waters 2487 2-channel UV/Visdetector. Tiacumincins were assayed on a 50×4.6 μm I.D., 5 μm YMC ODS-Acolumn (YMC catalog #CCA AS05-0546WT) with a mobile phase consisting of45% acetonitrile in water containing 0.1% phosphoric acid at a flow rateof 1.5 mL/minute. Tiacumicins were detected at 266 nm. An HPLCchromatogram of a crude product (Tiacumicin B retention time 12.6minutes) is shown in FIG. 1. In this example the crude yield ofTiacumicin B was about 250 mg/L after 7 days. After purification byHPLC, the yield of Tiacumicin B was about 100 mg/L.

Example 2

After standard sterilization conditions (30 min, 121° C., 1.05 kg/cm²)the seed flask (250 mL) containing Medium No. 104 (50 mL) was inoculatedwith AB 718C-41 NRRL 18085 and incubated on a shaker (set @250 rpm) at30° C. for 72 hr. Five percent vegetative inoculum from the firstpassage seed flask was transferred aseptically to a seed flaskcontaining the same ingredients as in Table 1 and was incubated on arotary shaker at 30° C. for 72 hr. Five percent inoculum from the secondpassage seed flasks was then used to inoculate with AB 718C-41 NRRL18085 in a 5-liter fermenter containing Medium No. 104 (2.5 L).Excessive foam formation was controlled by the addition of anantifoaming agent (Sigma A-6426). This product is a mixture ofnon-silicone organic defoamers in a polyol dispersion.

Glucose consumption was monitored as a growth parameter and its levelwas controlled by the addition of the feeding medium. Feeding medium andconditions in Example 2 were as follows:

-   Feeding medium:

Yeast extract Casamino acid Glucose K₂HPO₄ MgSO₄•7H₂O KCl 1.5% 1.5% 30%0.5% 0.5% 0.3%

-   Fermenter Medium: No. 104-   Fermenter Volume: 5 liters-   Sterilization: 40 minutes, 121° C., 1.05 kg/cm²-   Incubation Temperature: 30° C.-   Aeration rate: 0.5-1.5 volumes of air per culture volume and minute-   Fermenter Agitation: 300-500 rpm

The fermentation was carried out for 8 days and the XAD-16 resin wasseparated from the culture broth by sieving. After washing with waterthe XAD-16 resin was eluted with methanol (5-10×volume of XAD-16).Methanol was evaporated and the oily residue was extracted three timeswith ethyl acetate. The extracts were combined and concentrated underreduced pressure to an oily residue. The oily residue was dried andwashed with hexane to give the crude product as a pale brown powder andits HPLC chromatogram (Tiacumincin B retention time @11.8 minutes) isshown in FIG. 2. This was purified by silica gel column (mixture ofethyl acetate and hexane as eluent) and the resultant material wasfurther purified by RP-HPLC (reverse phase HPLC) to give Tiacumicin B asa white solid. The purity was determined to be >95% by HPLCchromatography and the chromatogram (Tiacumincin B retention time @12.0minutes) is shown in FIG. 3. Analysis of the isolated Tiacumincin B gaveidentical ¹H and ¹³C NMR data to those reported in J. Antibiotics, 1987,575-588, and these are summarized below.

-   Tiacumicin B:-   mp 129-140° C. (white powder from RP-HPLC);-   mp 166-169° C. (white needles from isopropanol);-   [α]_(D) ²⁰−6.9 (c 2.0, MeOH);-   MS m/z (ESI) 1079.7(M+Na)⁺;

¹H NMR (400 MHz, CD₃OD) δ 7.21 (d, 1H), 6.59 (dd, 1H), 5.95 (ddd, 1H),5.83 (br s, 1H), 5.57 (t, 1H), 5.13 (br d, 1H), 5.09 (t, 1H), 5.02 (d,1H), 4.71 (m, 1H), 4.71 (br s, 1H), 4.64 (br s, 1H), 4.61 (d, 1H), 4.42(d, 1H), 4.23 (m, 1H), 4.02 (pentet, 1H), 3.92 (dd, 1H), 3.73 (m, 2H),3.70 (d, 1H), 3.56 (s, 3H), 3.52-3.56 (m, 2H), 2.92 (m, 2H), 2.64-2.76(m, 3H), 2.59 (heptet, 1H), 2.49 (ddd, 1H), 2.42 (ddd, 1H), 2.01 (dq,1H), 1.81 (s, 3H), 1.76 (s, 3H), 1.65 (s, 3H), 1.35 (d, 3H), 1.29 (m,1H), 1.20 (t, 3H), 1.19 (d, 3H), 1.17 (d, 3H), 1.16 (d, 3H), 1.14 (s,3H), 1.12 (s, 3H), 0.87 (t, 3H);

¹³C NMR (100 MHz, CD₃OD) δ 178.4, 169.7, 169.1, 154.6, 153.9, 146.2,143.7, 141.9, 137.1, 137.0, 136.4, 134.6, 128.5, 126.9, 125.6, 124.6,114.8, 112.8, 108.8, 102.3, 97.2, 94.3, 82.5, 78.6, 76.9, 75.9, 74.5,73.5, 73.2, 72.8, 71.6, 70.5, 68.3, 63.9, 62.2, 42.5, 37.3, 35.4, 28.7,28.3, 26.9, 26.4, 20.3, 19.6, 19.2, 18.7, 18.2, 17.6, 15.5, 14.6, 14.0,11.4.

Example 3

A crude sample of Tiacumicin B (15 g) was obtained by fermentation as anoily residue after release from the resin as described in Example 2.This was dissolved in ethyl acetate (300 mL) at 35° C. and the solutionwas shaken in a separatory funnel with water (300 mL) and allowed tosettle for 1 minute. Saturated aqueous sodium chloride solution (100 mL)was added and the mixture was allowed to stand for a further 1 minute.The lower phase and any solids present at the interface were discardedand the upper phase was concentrated to a brown solid under reducedpressure at 35° C. The resulting foam was subjected to reverse phasemedium pressure liquid chromatography using a Biotage 75L apparatuscoupled to an Isco UA-6 UV/vis detector with the following parameters:

-   Column: 1.2 kg, Biotage KP-C18-HS silica.-   Equilibration: 50:50:1, MeCN/H₂O/AcOH (6 L).-   Loading: In methanol (20 mL) via sample injection module containing    25 g of Biotage KP-C18-HS silica.-   Eluent: 50:50:1, MeCN/H₂O/AcOH.-   Flow: 230 mL/min-   Pressure: Solvent—90 psi    -   Radial—100 psi-   Detector: Wavelength—254 mm    -   Path length—0.1 cm    -   Sensitivity—2    -   Chart speed—60 cm/hr.    -   Noise filter 5 sec.-   Fraction Collection: Manual—began collection just after inflection    between main peak and previous peak, ended collection at 20% of main    peak height.-   Column Conditioning: 100% MeCN (4 L)

Saturated aqueous sodium chloride solution (25% of the fraction volume)was added to the collected fraction. The mixture was shaken and allowedto separate into two phases. The upper phase was removed andconcentrated to dryness under reduced pressure at 30° C. The resultingsolid was dissolved in ethyl acetate (75 mL) and washed with water (2×75mL) to remove sodium chloride. The organic phase was concentrated underreduced pressure at 30° C. to a yellow foam (recovery: 4.56 g, 30%;purity ˜93%).

The material was combined with several other batches (total: 156.0 g,90.8% purity) and to this was added isopropanol (1000 mL). The mixturewas sonicated with stirring at room temperature for 20 min. to producean off-white suspension. At this point the material was filtered and thefilter cake was washed with isopropanol (300 mL). The solid was driedunder high vacuum to leave an off white powder (recovery: 146.2 g, 94%;purity: 91.1%) (FIG. 4). Mp 156-160° C.; [α]_(D) ²⁰−8.4 (c 2.0, MeOH);MS ink (ESI) 1079.7(M+Na)⁺; Calcd for C₅₂H₇₄Cl₂O₁₈: C, 59.03; H, 7.05;Cl, 6.70. Found: C, 58.75; H, 7.04; Cl, 6.91.

The inventions illustratively described herein can suitably be practicedin the absence of any element or elements, limitation or limitations,not specifically disclosed herein. Thus, for example, the terms“comprising,” “including,” “containing,” etc. shall be read expansivelyand without limitation. Additionally, the terms and expressions employedherein have been used as terms of description and not of limitation, andthere is no intention in the use of such terms and expressions ofexcluding any equivalents of the future shown and described or anyportion thereof, and it is recognized that various modifications arepossible within the scope of the invention claimed. Thus, it should beunderstood that although the present invention has been specificallydisclosed by preferred embodiments and optional features, modificationand variation of the inventions herein disclosed can be resorted bythose skilled in the art, and that such modifications and variations areconsidered to be within the scope of the inventions disclosed herein.The inventions have been described broadly and generically herein. Eachof the narrower species and subgeneric groupings falling within thescope of the generic disclosure also form part of these inventions. Thisincludes the generic description of each invention with a proviso ornegative limitation removing any subject matter from the genus,regardless of whether or not the excised materials specifically residedtherein. In addition, where features or aspects of an invention aredescribed in terms of the Markush group, those schooled in the art willrecognize that the invention is also thereby described in terms of anyindividual member or subgroup of members of the Markush group.

It is to be understood that the above description is intended to beillustrative and not restrictive. Many embodiments will be apparent tothose of in the art upon reviewing the above description. The scope ofthe invention should therefore, be determined not with reference to theabove description, but should instead be determined with reference tothe appended claims, along with the full scope of equivalents to whichsuch claims are entitled. The disclosures of all articles andreferences, including patent publications, are incorporated herein byreference.

1. A process of producing Tiacumicin B that comprises culturing amicroorganism having the ability to produce Tiacumicin B in a nutrientmedium and accumulating at least one Tiacumicin B in the nutrientmedium, wherein the yield of at least one Tiacumicin B is greater thanabout 50 mg/L of whole fermentation broth.
 2. A process according toclaim 1 wherein said yield is greater than about 100 mg/L broth. 3.(canceled)
 4. A process according to claim 1 wherein said yield is fromabout 50 mg/L broth to about 500 mg/L broth.
 5. (canceled)
 6. A processaccording to claim 1 wherein said microorganism is Dactylosporangiumaurantiacum NRRL
 18085. 7. (canceled)
 8. A process according to claim 1wherein said Tiacumicin B is isolated from said nutrient medium usingtechniques selected from the group consisting of: sieving and removingundesired material by eluting with at least one solvent or a solventmixture; extraction with at least one solvent or a solvent mixture;Crystallization; chromatographic separation; High-Performance LiquidChromatography (HPLC); MPLC; trituration; and extraction with saturatedbrine with at least one solvent or a solvent mixture.
 9. A processaccording to claim 1 wherein said microorganism is cultured at atemperature from about 25° to about 35° C. and at a pH from about 6.0 toabout 8.0.
 10. A process according to claim 1 wherein the nutrientmedium comprises one or more carbon sources selected from the groupconsisting of glucose, sucrose, starch, molasses, dextrins, whey,glycerol, lipids and corn meal.
 11. A process according to claim 1wherein the nutrient medium is fed with an additional carbon source asneeded.
 12. A process according to claim 1 wherein the nutrient mediumcomprises one or more nitrogen/organic sources capable of supportingmicroorganism growth selected from the group consisting of beef extract,soybean meal, whole yeast, yeast extract, soybean flour, peptone,casamino acid, fish powder, corn steep liquor, ammonium salts, caseinand amino acids.
 13. A process according to claim 12 wherein thenutrient medium comprises fish powder.
 14. A process according to claim1 wherein the nutrient medium comprises one or more inorganic saltscapable of supporting microorganism growth selected from the groupconsisting of K₂HPO₄, MgSO₄.7H₂O and CaCO₃.
 15. A process according toclaim 1 wherein the nutrient medium comprises at least one adsorbentcapable of adsorbing one or more Tiacumicin B during said culturingwherein said adsorbent is selected from the group consisting ofAmberlite XAD16, XAD16HP, XAD2, XAD7HP, XAD1180, XAD1600, IRC50,Duolite® XAD761 and a reverse phase silica gel.
 16. A process accordingto claim 15, wherein the reverse phase silica gel is selected from thegroup consisting of KP-C 18, KP-C 18-WP, and KP-C 18HS.
 17. A nutrientmedium for the production of Tiacumicin B from a microorganism, saidnutrient medium comprising a carbon source, a nitrogen source, traceelements, and an adsorbent, and wherein said nutrient medium is used toproduce Tiacumicin B in a yield greater than about 50 mg/L broth.
 18. Anutrient medium according to claim 17 wherein said Tiacumicin B yield isgreater than about 100 mg/L broth.
 19. (canceled)
 20. A nutrient mediumaccording to claim 17 wherein said Tiacumicin B yield is from about 50mg/L broth to about 500 mg/L broth.
 21. (canceled)
 22. A nutrient mediumaccording to claim 17 wherein said nitrogen source is fish powder.
 23. Anutrient medium according to claim 17 wherein said microorganism isDactylosporangium aurantiacum NRRL
 18085. 24. (canceled)
 25. A nutrientmedium according to claim 17 wherein the nutrient medium comprises atleast one adsorbent capable of adsorbing Tiacumicin B during saidculturing.
 26. A Tiacumicin B produced by culturing a microorganismbelonging to the species Dactylosporangium aurantiacum subspecieshamdenensis having the ability to produce and accumulate Tiacumicin B ina nutrient medium comprising a carbon source, a nitrogen source, traceelements such as inorganic salts, and an adsorbent, wherein saidnitrogen source comprises fish powder, and wherein said Tiacumicin B isproduced in a yield greater than about 50 mg/L broth.